CCL2 and obesity due to melanocortin 4 receptor deficiency: In obese individuals, dysfunctional adipocytes secrete proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), as well as chemokines, especially CCL2, which plays a major role in recruiting immune cells to ATs, resulting in obesity-associated metabolic inflammation [14].